New Study Explores Using Oceans and Lakes as Renewable Energy Resources

Jul 22, 2011

As the demand for energy increases worldwide, the search for renewable and viable sources of power intensifies. At Ryerson University in Canada, two researchers have taken that search underwater, and using Iran as a test case, have found that oceans and lakes could make an enormous contribution to global energy production.

“Bodies of water are a huge, untapped source of energy. They contain highly concentrated and highly dense forms of energy, which provide roughly the same amount of energy as thousands of solar panels and wind turbines,” said Alan Fung, a professor of mechanical and industrial engineering, and lead author of the paper, Review of Marine Renewable Energies: Case Study of Iran. The study analyzed the seas and lakes in Iran and surrounding areas to assess the potential of different types of marine energy.

As a renewable resource marine energy, unlike wind and solar energy, can be obtained at any time and can be stored free of charge. Bodies of water offer predictable amounts of energy, and in some cases, require smaller infrastructure (and less capital investment) to extract energy than other renewable sources of power. Harnessing marine energy is also more environmentally sustainable as conventional fossil fuel-fired electricity generation can cause pollution and lead to global warming.

While the technology to support certain types of marine energy is not yet commercially available, the researchers say their study shows that further investment is needed in order to make full use of this rich, renewable resource.

“You need to have a vision for the future,” said co-author Farshid Zabihian. “We shouldn’t wait until the technology is perfect to use marine energy. We can start right now by introducing it in smaller communities and through pilot projects.”

The data used in the study was provided by Zabihian, who studied power generation in Iran before moving to Canada to pursue a PhD in mechanical engineering at Ryerson. A former student of Fung, Zabihian graduated from Ryerson in June and will soon join the faculty of the West Virginia University Institute of Technology.

Using Zabihian’s data, the researchers examined the viability of five distinct types of marine energy. It was discovered that each one was specifically suited for Iran’s various bodies of water and could also be used in particular regions elsewhere in the world.

For example, wave energy, which is produced by the wind’s effect on water, does not require large areas of land in order to capture the energy from incoming waves. For that reason, this type of energy would be most effective on remote islands that are not connected to the power grid and where electricity is quite expensive. According to the World Energy Council, worldwide wave energy could potentially provide up to 12 per cent of current global electricity demand.

Tidal energy is created by the gravitational forces of the moon and the sun on the waters and rotation of the Earth. It is a highly predictable source of energy. Tidal energy takes the form of potential energy (the difference in water levels between ebb and flow) or kinetic energy (from the tidal current). As such, it could be used to replace or support conventional types of power generation.

Other types of energy examined by Fung and Zabihian include: ocean thermal energy, which relies upon the temperature difference between warm, shallow water and cold, deep water; ocean current energy, which requires the installation of underwater turbines to collect energy generated by wind and temperature differences in oceans due to solar heating; and salinity gradient energy, which produces energy from the osmotic pressure difference ( the amount of pressure needed to prevent a solution from flowing through a membrane) between fresh and salty water.

Review of Marine Renewable Energies: Case Study of Iran was published in the June 2011 issue of the journal Renewable and Sustainable Energy Reviews.